amino acid

noun

: an amphoteric organic acid containing the amino group NH₂

especially : any of the various amino acids having the amino group in the alpha position that are the chief components of proteins and are synthesized by living cells or are obtained as essential components of the diet

Examples of amino acid in a Sentence

Recent Examples on the Web

How protein fits into your daily diet Protein supplies the amino acids your body uses to repair muscle, produce enzymes and keep hunger in check. — Lauren Jarvis-Gibson july 9, Fort Worth Star-Telegram, 9 July 2026

Potential for Better Blood Pressure and Blood Flow L-citrulline is an amino acid in watermelon, especially in the white part of the rind. — Cynthia Sass, Health, 9 July 2026

An air of credibility Peptides are a string of amino acids — smaller than a protein — that often act as signaling molecules in our bodies and help regulate the immune system, metabolism and many other critical functions. — Will Stone, NPR, 8 July 2026

The liver produces ketone bodies by breaking down fat and amino acids, which the body uses for energy. — Mark Gurarie, Verywell Health, 7 July 2026

Word History

First Known Use

1897, in the meaning defined above

Rhymes for amino acid

• antacid
• placid

Kids Definition

amino acid

noun

ami·​no acid

ə-ˈmē-nō-

: any of numerous acids that include some which are the building blocks of proteins and are made by living cells from simpler compounds or are obtained in the diet

Medical Definition

amino acid

noun

: an amphoteric organic acid containing the amino group NH₂

especially : alpha-amino acid